1. Field of the Invention
The present invention relates to appliances such as food appliances and, more particularly, to appliances in which a mechanical lock is used to prevent activation of a motor or drive until a physical condition is satisfied such as when a cover is securely fastened on a food processor.
2. Description of Related Art
It is known in the art to provide mechanical activations means in various forms that activate a drive or motor when a device is in a condition such as a locked position for safety or proper function. Such devices are in a disabled mode when the condition is not met, such as when a lock or cover is not in place.
Specifically with respect to food processors, such as the one schematically shown in FIGS. 1–2. As shown in the exploded diagram of FIG. 1, a food processor base (10) has contained therein a motor and drive means (not shown) to engage and drive a blade shaft and blade (not shown) within a cylindrically shaped bowl (12) for chopping or mixing food. The motor or drive is rendered operable, or activated, only when a switch (14) is activated. A first rod (16) is located within a hollow channel (18) adjacent to a handle (20) outside of the bowl (12). The first rod (16) is biased by a spring (22) that engages a first flange (24) fixed to the rod (16). A second flange (26) is located at the top of the rod (16). Referring to FIG. 2, the first rod (16) is moved against the spring (22) by a downward force directed from a second rod (30) that is fixed to a plunger (28), when the plunger (28) is pushed into a food chute (32) which is integrally formed with a round lid (34) that covers the bowl (12). A channel (36) is provided for the second rod (30) to pass through. When the first rod (16) is moved as shown in FIG. 2, its lower end engages the switch (14) to activate the motor or drive in the base (10).
A problem associated with a design such as that described in FIGS. 1–2, is that when the second rod (30) is engaged as shown in FIG. 2, it is not possible to remove the lid (34) from the bowl (12), since the lid (34) locks relative to the bowl (12) by a relative rotational motion about axis Z in order to engage ramp wedges or bayonet lock features (not shown) commonly used on food processor lids. Thus, attempting to unlock the lid (34) from the bowl (12) by relative rotation would be prevented because the second rod (30) extends between the two and acts like a deadbolt or sliding lock. When it is desired to remove the lid (34) to access the inside of the bowl (12), therefore, it is necessary to first remove the plunger (28) from the food chute (32) to that the second rod (30) no longer impedes the rotational movement of the lid (34) relative to the bowl (12). This is cumbersome and may create a mess in the working space since food particles may be attached to the plunger (28). This problem is associated with known food processors of the type having a wide mouth feed chute, since these are designed to be disabled when the plunger is not inside the feed chute as a safety measure.
It is desirable, therefore, to provide a superior mechanical system for enabling and disabling a motor or drive in a food processor of the type having a wide mouth feed chute that facilitates removal of a lid from a bowl without the need to first remove the plunger.
These and other objects are achieved by the present invention described herein.